- Type: Chordata
- Diet: Insectivore.
- Size: Uncertain due to lack of remains, Skull length about 17 millimetres.
- Protection status: Extinct
- A rather small and unassuming little creature, Adelobasileus is an evolutionary giant because it helps to bridge the gap between cyonodonts and later primitive mammal forms of the Triassic. At the time of its description, it was the earliest known proto-mammal. Because of its small size, Adelobasileus was probably an insectivore in its behaviour, but one that needed to keep out of sight of early dinosaurs such as Coelophysis.